This invention relates to an explosively-actuated mechanism automatically operable upon the occurrence of a predetermined event to release a breathing mask from a protective helmet sufficiently to enable the user to breathe the ambient atmosphere independently of the mask.
Pilots and other aircraft crew members customarily are provided with breathing mask-protective helmet arrangements wherein the mask is releasably secured to the helmet in a manner positioning the mask snugly against the face of the wearer. Typically, such arrangements include a mask mounting harness terminating at opposite ends in bayonet connectors which cooperate with bayonet-receiving means mounted on opposite sides of the helmet for releasably securing the mask to the helmet. Each bayonet commonly includes spring fingers, and each bayonet-receiving means includes a cover plate and other components held together in assembled relationship defining a bayonet-receiving channel for accepting the bayonet and which interlock with the spring fingers when the bayonet is operatively positioned within the channel. The aviator is thereby enabled to push each bayonet into its corresponding bayonet-receiving channel until the mask fits comfortably and snugly against the face, and the bayonet-receiving means serves to lock the mask in such position of use. The mask typically is provided with a face-contacting cushion of resilient material which is compressed against the face of the user to provide a seal when the mask is locked in such position of use. The bayonets are provided with a manually-actuated release mechanism so that the aviator can manually release the bayonets from the helmet-mounted receivers. Typically such mechanisms include a release bar carried by the bayonet which bar is manually shiftable relative to the bayonet to retract the spring fingers and thereby release the interlock, the release bar having a manually engageable member externally of the bayonet-receiving means for that purpose.
Breathing gas is supplied to the interior of the mask through a hose connected at one end to the mask and having its other end connected through a quick disconnect coupling to a source of breathing fluid carried by the aircraft. Upon ejection of the aviator from the aircraft, the hose is released from its source connection, remaining attached to the mask as the aviator descends. This presents a potential problem if the aviator descends into water, because of the need to separate the mask from his face. While the manual release mechanism presumably will remain operative, often the aviator will be unconscious or injured and unable to manually release the mask. In that event, he can breath only through the mask and attached hose, and will inhale water and shortly drown if the mask remains secured against his face.
U.S. Pat. No. 4,488,546 dated Dec. 18, 1984 discloses a connector associated release mechanism automatically operable upon immersion in water to shift the release bar mechanism in a manner simulating manual actuation thereof. To this end, a normally rigid water sensitive element is provided which loses its rigidity in water, permitting a compression spring to relax and thereby shift the release bar mechanism to disengage the spring fingers.
Pending U.S. patent application Ser. No. 922,075, filed Oct. 20, 1986, now U.S. Pat. No. 4,803,980, entitled AUTOMATIC BREATHING MASK RELEASE MECHANISM and having the same assignee as the present application discloses an automatic release mechanism which is incorporated into the bayonet-receiving means on the helmet for automatically and explosively separating the bayonet from the bayonet-receiving means in response to the occurrence of a predetermined event, such as the presence of water. The mechanism includes an explosive cartridge and an associated piston mounted within the bayonet-receiving means. When activated, the explosive charge drives the piston at generally a right angle against the bayonet, driving the latter against the cover to separate the latter from the bayonet-receiving means and eject the bayonet from its receiving channel, all independently of the manually actuated release mechanism. Reference is made to said application for a more detailed description of the disclosed automatic release mechanism.
The explosively activated release mechanism of application Ser. No. 922,075 has particular utility where it is desired to ensure release of the mask by a positive displacement action as described above.
In some instances it is desired to provide the positive action achieved with an explosively activated mechanism in a more contained arrangement, and that is accomplished by the present invention.
It is an object of the present invention to provide an explosively-activated mechanism for releasing a breathing mask from a protective helmet in a relatively confined and contained manner.
Another object of the present invention is to provide the foregoing in a mechanism which achieves the desired mask separation while reducing the likelihood that any portion of the bayonet-receiving means or of the bayonet is forceably propelled away from the helmet by the explosive action of the mechanism.
Still another object of the present invention is to provide such a mechanism wherein components of the bayonet-receiving means are separated by the explosive force of the mechanism, when activated, and the resilient action of the mask cushion against the face is utilized to assist in thereupon separating the bayonet from its receiving means.
Yet another object of the present invention is to provide the foregoing in a mechanism which is relatively uncomplicated, highly dependable and which operates independently of the manually actuated release and is totally compatible with the environment of its intended use.